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(IoIodaL) C. A. RANDALL. Telephone System and Apparatus.

(53 52 wists Patented Nov. 30,1880.

M may luulmmn t UNITED STATES PATENT OFFICE.

CHARLES A. RANDALL, OF NEW YORK, N. Y.

TELEPHONE SYSTEM AND APPARATUS.

SPEOHFTCATION forming part of Letters Patent No. 285,020, dated November 80, 1880.

Applimtiunfiled Mays, 1880. (So model.)

1'0 all whom it may comm:

Be it known that I, CHARLES A. RANDALL, a citizen of the United States, residing at New York, in the county of New York and State of New York, have invented new and useful Improvements in Telephone Systems and Apparatus, of which the following is a specification.

This invention relates toatclephone system in which an electric main-line cireuit is alternately made and broken in a manner similar to the making and breaking of the circuit in the Morse system of telegraph except that the makes and breaks are in correspondence with the vibrations of a diaphragm or its equivalent actuated by air-vibrations, instead of being produced by a key making the dots and dashes of the Morse alphabet It has heretofore been considered impossible to transmit articulate tunes by actual make and break of the circuit at the transmitting-instrument, and all telephones now in useare worked on the closed-circuit principle, with undulatory currents. The comparatively small electro-motive force that can be utilized in nndulatory currents, the extreme sensitiveness necmary in the instruments, the deliarcy of adjustments required, and the very limited length of the circuits that can be worked efl'iciently are serious disadvantages to telephonic communication; and to overcome these disadvantages is the object of my invention. This object I have in a great degree accomplished by rendering possible the actual make and-break of the circuit in correspondence with the movements of the primary vibrator of the transmitting-instrument, thus utilizing almost the entire electro-motive force of the battery for operating the receiver, in which, therefore, less delicate adjustments than heretofore are required, by enabling the use of batteries of great electro-motive force, by working main-line receiving-instrument or receiver-relay by a direct battery-current instead of an induced current, and by operating the final or telephonic receiver by means of a local circuit.

The operation of my improved system re quires a circuit-breaking transmitter in a main-line circuit, with a receiving electromagnet, which, in turn, controls the telephonic receiver in a local circuit.

The transmitter is so constructed that the contact-points may be adjusted very close to each other without actual contact, and one or both of these contact-points should be slightly yielding, so that varying contact-pressure may be had, and so arranged as to be controlled by the vibrations of the diaphragm or other primary vibrator, the effect of which vibrations I preferably magnify by connecting with said vibrator the short arm of a lever having the end of its long arm arranged to operate the contact-points.

The receiving apparatus comprises an e1ectro-maguet in the main circuit, han'ng its armaturc adjusted to rapidly respond to the variations and cessations of magnetic influence, and connected with a tension-changer in a local circuit, which circuit also includes the telephonic receiver, which may be of any wellkuown and suitable construction.

In the accompanying drawing are shown side elevations of the transmitting and receiving apparatus constructed substantially as required for the operation of my improved telephone system.

The letter A designates the diaphragmframe, provided with a mouth-piece, b, and supported by a standard, c. The diaphragm, which may be supported in the frame in any approved manner, is indicated by the broken line, as at D.

From the upper part'of frame A a stud, 0, projects rearward, and has pivoted to its outer 85 end a pendent lever, F, from which an arm, 9, extends to, and is preferably connected with, the diaphragm, said arm being also preferably pivoted to the lever.

The lever F is connected by a spring, f, with an adjusting-screw, f, in standard c, and at its lower end the said lever carries an elastic cushion, k, preferably of india-rubber, which is in contact with the upper portion of a leafspring, I, rising from the base k and connected with the screw-post I.

From the face of the spring I opposite that which is in contact with the cushion projects a platinum stud, a, toward a plumbago button, N, which is carried by a leafspring, 0. mo

The lower end of the leaf-spring O is firmly secured to the arm 12. which is pivoted at p and extends rearwardly. A screw, q, passes through the arm 12 and bears upon the base, its ofiice being to adjust the arm for a purpose which will presently appear. The upper end of the spring 0 bears against the tip of an adjusting-screw, 1', arranged in a bracket, 1', projecting from a standard, 8.

By adjusting the arm up or down the tension with which the spring 0 bears against the screw 1' may be regulated, and by means of said screw 1- the position of the spring may be adjusted so as to bring the plumbago button N to the proper distance from the platinum stud m.

By means of the adjusting-screw f and spring fthe lever Fis adjusted to cause the arm 9 to bear with proper pressure upon the diaphragm, and also to cause the said lever to 2' promptly resume its normal position after being thrown rearward by the diaphragm, when the arm 9 is not attached to the said dia- 5 phragm. r

The transmitting-instrument which has now been described is connected with one pole of the battery B by means of a wire, 1', leading from the screw-post I, and with the line-wire L by means of a binding-screw and socket in g the arm p. The circuit is from the battery to the leaf-spring I, thence to the plumbago button N, when the platinum stud is in contact therewith, and from said button over spring g 0 and arm 1) to the line.

In the receiving apparatus, on the left-hand side of the drawing, the letterT designates an electro-magnetmounted on a base, 1, and T is its armature, carried by a metallic spriugarm, U, attached at one end to a metal post, 5 U, and carrying at the other end a platinum stud, c, which bears upon a plumhago button, V, carried by a leaf-spring, r, projecting from a metal post, 1'', which is connected by wire uwith one pole of a local battery, B, which has its other pole connected with one terminal of the telephone W, the other terminal of which is connected with the spring-arm U through post U. The circuit is from the battery to the telephone over wire 10, and from the tele phone to post U over spring-arm U, plumbago button V, leaf-spring r, post; 2'', and thence back to the battery. One terminal of the electro-magnet T leads to a screw-post, r, with which the main line L is connected, and the other terminal leads to a screw-post, z, 1 which is connected with the ground. 1

The operation of the apparatus herein shown and described is as follows: Upon speaking into the mouth-piece of the transmitting apparatus there is given to the diaphragm a to-andfro movement, the effect of which is increased in force and amplitude at the circuit-closerviz., the plumbago button M and platinum stud mby means of the lever. These rapid to-and-fro movements alternately make and break the current over the main line, which currents, in turn, pass over and through the receiving-magnet; T of the receiving apparatus, and cause avarying attraction of its armature corresponding to the amplitude of the vibrations of the diaphragm, said varying attraction and non-attraction of the armature causing a varying contact between the carbon button V and platinum stud u-iu the local circuit, having the local battery and the telephonic receiver therein, so that the electrical impulses over the telephonic receiver correspond in number and in varying power to the vibrations of the diaphragm and the amplitude of its movements.

There are various modifications that may be made, such as using an induction-coil at the receiver, the primary coil being in circuit with the battery and a tension-changer, and the telephonic receiver in the secondary circuit, as well as other changes, without departing from the spirit of my invention.

What I claim is 1. The combination, in a telephone system, of a main line, a transmitter arranged to make and break the circuit of said main line by the vibrations of its diaphragm or similar vibratois moving in response to sound-vibrations, a

local circuit including a telephone-receiveraud a tension-changer, and an electro-magnet in the main circuit arranged to control said tension-changer, substantially as set forth.

2. The combination, in a telephone apparatus, of the lever F, arranged to be operated by the vibrations of the diaphragm, of the leafspring I, leaf-spring O, and suitable intermediate contact devices, said springs being ar ranged to form a portion of the main line when contact is made between them, substantially as described.

3. The combination, with the lever F, operated by the vibrations of the diaphragm, and the leaf-spring operated by the said lever, of the spring 0 and devices for adjusting the tension of the same, substantially as described.

In testimony whereof I have hereunto set my hand in the presence of two subscribing witnesses.

CHARLES A. RANDALL.

Witnesses:

HARRY C. Brncn, OLE H. HOLBERG.

I GO 

